A hard cold front is a real test for any heating system. Depending on the type of heat you have, here is what to expect and what to watch for.
Heat pumps
Heat pumps work hard in these temperatures. With moisture in the air, the defrost cycle will run every 30, 60 or 90 minutes depending on your setup, and can stay in defrost for up to 15 minutes each time. Auxiliary heat is essential during defrost and sub-freezing weather.
- Around 25–30°F, expect the heat pump to run continuously, with the aux heat coming on often.
- Around 15–25°F, frost may not fully clear and the heat pump loses a lot of its capacity.
- Below 10–15°F, consider switching the thermostat to emergency heat. That turns off the heat pump and runs the backup heat on its own, which by then is doing nearly all the work anyway.
90+ condensing gas furnaces
Gas furnaces keep up easily in this weather, so let them run. A few tips:
- Condensing furnaces make water. If the drain runs outside it can freeze. Temporarily move it to a wash sink or bucket, or add heat tape where it exits.
- If the exhaust pipe leaves through a side wall, check it often. Exhaust can freeze at the outlet, and a frozen bird screen can block the flue, which is dangerous.
Oil furnaces
Oil furnaces also keep up fine. The usual trouble is the fuel supply:
- Wrap exposed oil lines in pipe insulation and add heat tape.
- Lines that leave the bottom of the tank can freeze or gel if there's moisture. Wrap them too.
- Keep the tank as full as you can.